Anti-pilferage devices as proposed by AAR regulations must meet the following requirements.
The device is to be located considerably above the top of the rail so that it is difficult to reach in the yard except from a loading dock.
The device is to accept an additional locking device such as a car seal, a cable of at least 1/2 inch in diameter, or a lock, such as a padlock. In operation, the seal cable or lock must not be subjected to opening loads.
On a plug door, the device is to be located on the crank arm operating rod so that the crank arm cannot rotate and the door cannot be withdrawn from the closed and locked position.
In addition to the above requirements, some railroads have indicated that a self-latching feature is desirable wherein the device provides determent without a seal or lock inserted.